Arsenal have received a massive blow with Santi Cazorla being diagnosed with ligament damage on his knee, piling on Arsene Wenger's woes in central midfield. The Gunners already have Mikel Arteta, Jack Wilshere, Tomas Rosicky and Francis Coquelin out through injury in that position and Cazorla's absence will bring the north London club down to their knees in terms of personnel available.

The Guardian reports that the initial assessment was for Cazorla to miss the Olympiacos game but scans have shown that the injury is much worse than feared, with chances of the midfielder missing months rather than days on the sidelines. A similar fate has befallen Coquelin, who has also been ruled out of contention for three months after coming out second best in a challenge against West Bromwich Albion.

Wenger is looking to integrate Calum Chambers into the first team at this point where he will be used as an option in defensive midfield while Mathieu Flamini is likely to keep his place in the squad till the former Southampton man is properly grilled in training and other reserve games. The manager will also be boosted by the imminent return to action of Wilshere, who has confirmed that he is recovering faster than initially thought and could be back in action before the end of the year.

Aaron Ramsey will slot into Cazorla's position in his absence, with the Welshman finally getting a chance to prove his worth in central midfield after being shunted to the wings recently. Meanwhile, Alexis Sanchez, who pulled up a hamstring against Norwich, is also expected to miss three to four weeks. However, Laurent Koscielny, who was substituted early in the first half, does not have a serious problem and is likely to be back in training before the game against Sunderland.

The Gunners will be boosted by the return of Alex Oxlade-Chamberlain, who came on as a substitute against Norwich, while Theo Walcott is also close to returning to action.